The screens are used especially in the mining industry for classifying pellets as to size. A series of motor-driven parallel rolls are mounted on a bed frame with specific gaps between the individual rolls. The screen is inclined and can be made of a single roller deck or a double roller deck. The double roller deck is composed of an upper and a lower deck and its function is described below. The pellets are discharged onto the upper deck. All pellets having a larger size than the upper deck roll gap (oversized pellets) are transported to the end of the upper deck. All pellets having a smaller size than the upper deck roll gap are passing through these gaps onto the rolls of the lower deck. All pellets having a larger size than the lower deck roll gap (correct size pellets) are transported to the end of the lower deck. All pellets having a smaller size than the lower deck roll gap (undersized pellets or fines) are passing through these gaps. The roll surface becomes pitted and worn due to abrasion produced by the pellets and, therefore, the roll gap must be adjusted from time to time. The roll gaps may also need to be adjusted upon different pellet sizes required and specified by any specific end customer. This adjustment is conventionally a manual operation requiring bolting and unbolting of the individual rolls pillow blocks and adjustment of the gap by means of wedges or gauges inserted between the rolls at each end of the same. This is a time consuming operation.